1. Field of the Invention
The present invention relates to a video recording and reproducing apparatus that records video data received from broadcasting or communications and reproduces the record video data and to a method for controlling the same. In particular, it relates to a video recording and reproducing apparatus that has the function of improving image quality of recorded video data and to a method for controlling the same.
2. Description of the Related Art
The maximum number of effective pixels in current standards for digital broadcasting in Japan is 1,920×1,080 pixels in the high definition (HD) format. However, techniques for broadcasting high-definition contents that have a large number of pixels exceeding the number of pixels in HD are under development. Examples of such techniques include the super high definition (SHD) format and the ultra-high definition (UHD) format being developed by NHK (Japan Broadcasting Corporation). The maximum number of pixels in techniques now being developed is 7,680×4,320 pixels, which significantly exceeds the number of pixels in the HD format. For the SHD and UHD formats, a higher quality of not only video but also audio is under development. For example, a system that has 22.2 channels as voice channels has been produced and demonstrated.
However, it is estimated that contents broadcast with a lower image quality and audio quality in, for example, the standard definition (SD) coexist with contents having a larger number of pixels.
A technique for improving the image quality and audio quality of non-high quality contents that have a smaller number of pixels and a smaller number of voice channels than those of high quality contents using a high-performance arithmetic unit and a complex algorithm (hereinafter referred to as up-converting) over time is proposed.
There are techniques for automatically improving the image quality of a video content depending on the remaining amount of a storage medium when the video content is stored thereon to efficiently up-convert a video content (e.g., broadcasting program). One such technique is described in Japanese Patent Laid-Open No. 2004-228837.
Unfortunately, for the technique described in this patent document, the image quality of a program desired by a user is not always improved. For example, in this technique, even when improvement in the image quality of a program to be recorded is not desired, if the storage medium has enough available storage space, the content is automatically subjected to a process of improving the image quality to be stored. If this content is an originally high-quality content, the degree of improvement may be less than expected although the content has been up-converted over time.
Because the image quality of video contents currently broadcast is either SD or HD, a user can make the settings for an up-converting process by choosing between only two things. However, as described above, contents with higher qualities, such as in the SHD or UHD format, will become commercially available in the near future. For video transmission via a network, various kinds of video contents from a content that has a smaller number of pixels and a lower bit rate than a content with the SD image quality to a content whose image quality is equal to the HD image quality are now available. In an environment where a wide variety of video contents are available, it is difficult for an ordinary user to determine what video content can be up-converted to what quality level.